Glare prevention feature

ABSTRACT

The subject invention relates to an automotive front lamp assembly with a reflector and a light source and relates to a manufacturing defect that causes a substantial amount of glare when light from the light source strikes it. The subject invention utilizes at least one glare prevention to cover or prevent the formation of the sink. In an exemplary embodiment, the glare prevention feature comprises a rib or half-sphere with a convex surface that has a sharp radius. The convex surface spreads out the light that reflects off it over a large area in order to prevent glare. In another embodiment of the subject invention, the glare prevention feature comprises a rib with a substantially perpendicular surface and an angled or curved surface. This embodiment prevents glare by redirecting most of the light that strikes its surfaces so that it is not emitted out of the front lamp assembly.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a divisional application of U.S. patentapplication Ser. No. 10/633,900 filed Aug. 4, 2003.

BACKGROUND OF THE INVENTION

Automotive forward lamp assemblies have been modified over the years todecrease the overall mass of the assemblies in order to increase thesafety and the gas mileage of automobiles. Most conventional automotiveforward lamp assemblies require a large amount of mass concentration atthe front of the vehicle. For example, a typical headlamp and fog lampassembly will comprise a housing with a reflector, at least one filamentbulb, a plurality of electrical wires and a lens. This constructionresults in a large mass concentration located at the front of thevehicle. In the event of a vehicular accident, a large massconcentration at the front of the vehicle is undesirable because it canresult in increased damage and increased injuries. This is especiallyproblematic in the event an automobile collides with a pedestrian.

In an effort to reduce the mass of automotive front lighting systems,designers have begun using thermoplastic materials to construct thereflector for headlamp and fog lamp assemblies. Thermoplastic reflectorshave the advantage of having less mass than other types of reflectors.Thus, thermoplastic reflectors reduce the overall weight of the lampassembly. Unfortunately, thermoplastic materials have the drawback ofcreating manufacturing defects in the form of sinks. As used herein, theterm “sink” is used to describe a manufacturing defect located on thereflector that forms a pit in the reflector (i.e. an indentation, arecess and/or a concave surface). A sink causes a large amount of glareto be emitted from the lamp assembly because the defect reflects lightin such a manner that a large amount of light is concentrated over asmall angle when light reflects from the sink. Concentration of lightover a small angle can result in unwanted glare or bright spots in thebeam pattern. Thus, sinks are detrimental to the optical performance ofan automotive lamp assembly because they cause the lamp assembly to emita large amount of glare. Sinks occur frequently in the manufacturing ofheadlamp reflectors because of the thick sections required to form thereflector. For example, a sink normally forms around the socket hole ofthe reflector. While this is an example of a normal location of a sink,sinks of all shapes and sizes are also prone to appear in other portionsof the reflector. In order to use thermoplastic reflectors tomanufacture headlamp assemblies, designers of headlamp assemblies arefaced with overcoming the glare problems associated with sinks.

Accordingly, it is desirable to have an automotive forward lamp assemblythat would allow for the use of a thermoplastic reflector without havingthe large amount of glare resulting from a sink in the thermoplasticreflector. Specifically, it is desirable to develop a design featurethat can eliminate the optical problems caused by sinks on thermoplasticreflectors.

BRIEF SUMMARY OF THE INVENTION

In order to prevent a sink from forming on a reflector, one exemplaryembodiment of the subject invention comprises a automotive front lampassembly with a reflector that has at least one glare prevention featurewhere normally a sink would form. The glare prevention feature of thisembodiment comprises a convex reflective surface that has a relativelysharp radius. The term “sharp radius” defines a convex surface with arelatively small radius such that the convex surface forms an arc thatadequately disperses light. While light from a concave reflectivesurface, as is common with the sinks discussed herein, will tend toconcentrate along a particular axis, light reflected from a convexreflective surface will tend to dissipate in different directions. Theconvex surface can be a convex rib with a sharp radius or a half-spherewith a sharp radius. The sharp radii of these two embodiments allowthese two glare prevention features to spread out the light that strikesits surface over a large area in order to prevent glare from beingemitted from the lamp assembly. In another embodiment of the subjectinvention, the glare prevention feature comprises a rib with asubstantially perpendicular surface and an angled or curved surface.This embodiment prevents glare by redirecting most of the light thatstrikes its surfaces so that it is not emitted out of the front lampassembly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded front view of an exemplary headlamp assembly ofthe subject invention;

FIG. 2 is a cross-sectional view of the reflector of the exemplaryheadlamp assembly of FIG. 1 along line A-A;

FIG. 3 is a cross-sectional view of the reflector of the exemplaryheadlamp assembly of FIG. 1 along line C-C without the glare preventionfeature;

FIG. 4 is a cross-sectional view of the reflector of the exemplaryheadlamp assembly of FIG. 1 along line C-C with the glare preventionfeature;

FIG. 5 is a front view of a reflector of an exemplary fog lamp assemblyof the subject invention without a lens and without a light source;

FIG. 6 is a cross-sectional view of the reflector of FIG. 5 along lineB-B;

FIG. 7 is a front view of another exemplary embodiment of the subjectinvention without a lens and a light source;

FIG. 8 is a front view of another exemplary embodiment of the subjectinvention without a lens and a light source;

FIG. 9 is a cross-sectional view of the glare prevention feature alongline D-D of FIG. 8;

FIG. 10 is a front view of another exemplary embodiment of the subjectinvention without a lens and a light source; and

FIG. 11 is a cross-sectional view of the glare prevention feature alongline E-E of FIG. 10.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows an exploded view of an exemplary embodiment of anautomotive lamp assembly that utilizes a glare prevention feature. Asshown in FIG. 1, the exemplary embodiment comprises automotive frontlamp assembly 45. Front lamp assembly 45 comprises a lens 20 connectedto a lamp housing 25 by means well known in the art. For example, anadhesive/sealant can be placed on either lamp housing 25 or lens 20 inorder to join them together. Lamp housing 25 contains a reflector 50. Inthis embodiment, reflector 50 comprises a thermoplastic reflector havinga socket hole 40 that accepts and holds a light source 30. Reflector 50is mounted within lamp housing 25 by means well known in the art. Forexample, an adhesive can be used to mount the reflector to the lamphousing or the reflector can be snapped into the lamp housing. A glareprevention feature 35 is located on reflector 50. As described in moredetail below, glare prevention feature 35 is a thickened portion of thereflector that is formed on the reflector to prevent, at least in part,the formation of a sink and/or to fill or partially fill a recessed areaon the reflector where a sink exists. While reflector 50 is athermoplastic reflector in this embodiment, it will be appreciated byone skilled in the art that the reflector can comprise any number ofreflectors known in the art.

FIG. 2 is a cross-sectional view of front lamp assembly 45 along lineA-A of FIG. 1. As shown in FIG. 2, reflector 50 has a thick section 60around socket hole 40 and glare prevention feature 35 located in frontof the thick section. If glare prevention feature was not present, asink 55 would form in front of thick section 60. Glare preventionfeature 35 is molded in the place where sink 55 would form (shown bydotted line in FIG. 2) in order to prevent the formation of the sink andthe associated glare problems therewith. Glare prevention feature 35 isa rib 34 with a convex surface 36 that has a sharp radius. The sharpradius of glare prevention feature 35 causes light to spread out over avery large area and reduces the intensity of any light that strikes andreflects off of its surface. This sharp radius prevents glare bypreventing light from hitting the convex surface of sink 55 and beingreflected off of sink 55 over a small angle. Thus, a designer of frontlamp assemblies can prevent the glare caused by sink 55 by molding glareprevention feature 35 in the place where the sink would form.

Glare prevention feature 35 forms and becomes part of reflector 50during the manufacture of the reflector. Reflector 50 is manufactured byan injection molding process well known in the art. A designer candetermine where sink 55 is located by molding a first reflector with aninjection molding tool. The first reflector will not have glareprevention feature 35. FIG. 3 shows a cross-sectional view of front lampassembly 45 along line C-C of FIG. 1 without glare prevention feature 35included in the lamp assembly. As shown in FIG. 3, sink 55 is located infront of thick section 60 of reflector 50. Instead of molding a firstreflector, a designer could predict where the sink would be located byanalyzing the design (i.e. a part drawing) of the reflector. The sinkwill be located in front of the thick section. Once the location andsize of sink 55 is determined, a designer can create glare preventionfeature 35 by cutting into the injection molding tool the desired shapeand size of the glare prevention feature at the location where sink 55appears. The designer can then injection mold a reflector with thealtered injection molding tool and glare prevention feature 35 will bemolded in the place where sink 55 would have formed.

FIG. 4 shows a cross-sectional view of front lamp assembly with glareprevention feature 35 along line C-C of FIG. 1. As shown in FIG. 4,glare prevention feature 35 is molded in the place where sink 55 (shownby the dotted line) would form on reflector 50. In this manner, adesigner can prevent sink 55 from forming by molding glare preventionfeature 35 in the same location. Glare prevention feature 35 willprevent glare from being emitted from the front lamp assembly. It willbe appreciated by one skilled in the art that other methods of creatingthe glare prevention feature can be utilized to manufacture the subjectinvention. For example, the designer could physically cover any sinkformed on the reflector with the glare prevention feature instead ofcausing the glare prevention feature to be molded where the sink wouldnormally form. Further, while the glare prevention feature comprises thesame material used to create the reflector in this embodiment, it willbe appreciated by one skilled in the art that various other materialscan be used to manufacture the glare prevention feature.

Glare prevention feature 35 does not have to be molded in a way thatprevents the entire sink 55 from forming. While preventing all of theformation of sink 55 is necessary to prevent all glare produced by thesink, it may be desirable for a designer to reduce the glare instead ofentirely eliminating it. FIG. 5 shows a front view of another exemplaryembodiment of the subject invention without its light source and itslens. As shown in FIG. 5, the exemplary embodiment comprises fog lampassembly 65 with reflector 50 and lamp housing 25. Reflector 50 hassocket hole 40 located in the center of the reflector and glareprevention feature 35 located on the reflector. FIG. 6 shows across-sectional view of fog lamp assembly 65 along line B-B of FIG. 5.As shown in FIGS. 5 and 6, glare prevention feature 35 only prevents theformation of a portion of sink 55. By partially preventing the formationof sink 55, the glare can be reduced to meet the desired lightingrequirements for the particular automotive front lamp assembly beingcreated.

Glare prevention feature 35 can be located anywhere on reflector 50 andcan be any shape and size necessary to prevent the formation of anynumber of sinks 55. FIG. 7 shows a front view of automotive front lampassembly 70 without its lens and its light source. As shown in FIG. 7,automotive front lamp assembly 70 comprises reflector 50 and lamphousing 25. Reflector 50 has socket hole 40 in the center of thereflector and plurality of glare prevention features 35 located on thereflector. Each of the plurality of glare prevention features 35 can besmall in size and located anywhere on reflector 50 in order to preventthe formation of any sink 55 on the reflector. It will be appreciated byone skilled in the art that the glare prevention feature can comprisemany different shapes and designs in order to prevent the formation ofthe sink or sinks on the reflector.

FIG. 8 shows another exemplary embodiment of the subject inventionwithout its lens and its light source. As shown in FIG. 8, thisexemplary embodiment comprises front lamp assembly 75 having reflector50 and lamp housing 25. Reflector 50 has socket hole 40 located in thecenter of the reflector and plurality of glare prevention features 35located on its surface. In this embodiment, each of the plurality ofglare prevention features 35 comprises a half-sphere with a sharpradius. Plurality of glare prevention features 35 prevent the formationof sink 55 by being molded on reflector 50 where the sink would form.FIG. 9 shows a cross sectional view along line D-D of FIG. 8 of one ofthe plurality of glare prevention features 35 on reflector 50. As shownin FIG. 9, each individual glare prevention feature 35 forms a convexsurface where sink 55 (shown by dotted line) would have been located. Asalready described, this prevents glare by spreading any light thatstrikes the convex surface over a large area.

Glare prevention feature 35 can also comprise a rib that redirects thelight into a non-reflective surface such as the sidewall or the floor oflamp housing 25. FIG. 10 shows another exemplary embodiment of thesubject invention without its lens and its light source. The exemplaryembodiment comprises front lamp assembly 80 having lamp housing 25 andreflector 50. Reflector 50 has socket hole 40 located in the center ofthe reflector and glare prevention feature 35 located on its surface.FIG. 11 shows a cross sectional view along line E-E of FIG. 10 of glareprevention feature 35. As shown in FIG. 11, glare prevention feature 35of this embodiment comprises a rib with a substantially perpendicularsurface 82 and a curved surface 84. Substantially perpendicular surface82 is substantially perpendicular to reflector 50. In this embodiment,glare prevention feature 35 is located where sink 55 (shown by dottedline) would have formed. As a result, most of the light that hits theglare prevention feature's surface will be redirected into anon-reflective surface, such as the side-wall or floor of lamp housing25. Thus, glare prevention feature 35 prevents glare by redirecting thelight in a manner that does not allow it to pass out of lens 20 (notpictured). While glare prevention feature comprises curved surface 84,it will be appreciated by one skilled in the art that the surface can beangled in such a way to cause the light to be redirected in the desiredmanner. It will also be appreciated that glare prevention feature 35could also redirect the light into a reflective surface that eitherspreads the light out so that it does not cause glare or into areflective surface that will cause the light to continuously bereflected until it dissipates.

While the subject invention has been described in considerable detailwith references to particular embodiments thereof, such is offered byway of non-limiting examples of the invention as many other versions arepossible. For example, one could cover a sink located on a reflectorwith a glare prevention feature instead of molding the glare preventionfeature where the sink would normally be. The sink could be filled withan epoxy to form a convex surface over the sink and then the epoxysurface could be covered with a reflective coating so that light thathits the glare prevention feature will be reflected over a large angle.It is anticipated that a variety of other modifications and changes willbe apparent to those having ordinary skill in the art and that suchmodifications and changes are intended to be encompassed within thespirit and scope of the pending claims.

1. An automotive front lamp assembly comprising: a. a reflector; and b.at least one glare prevention feature located on the reflector toprevent the formation of at least one sink.
 2. The automotive front lampassembly of claim 1, wherein the reflector comprises a thermoplasticreflector.
 3. The automotive front lamp assembly of claim 1, wherein theat least one glare prevention feature comprises a rib with a reflectiveconvex surface having a sharp radius.
 4. The automotive front lampassembly of claim 1, wherein at least one glare prevention featurecomprises a reflective half-sphere having a sharp radius.
 5. Theautomotive front lamp assembly of claim 1, wherein the at least oneglare prevention feature comprises a rib with a substantiallyperpendicular surface to the reflector and a curved surface.
 6. Theautomotive front lamp assembly of claim 1, wherein the at least oneglare prevention feature comprises a rib with a substantiallyperpendicular surface to the reflector and an angled surface.
 7. Theautomotive front lamp assembly of claim 1, wherein the at least oneglare prevention partially prevents the formation of the at least onesink.
 8. A method of preventing glare from being omitted from a frontlamp assembly comprising the steps of: a. providing a reflector with atleast one sink; b. providing at least one glare prevention feature; andc. covering the at least one sink with the at lest one glare preventionfeature.